Which human-made object has reached the greatest speed?

The Parker Solar Probe is the fastest human-made object ever built, setting the speed record during close passes by the Sun. It uses repeated Venus flybys to shrink its orbit and accelerate closer to the Sun’s gravity well. At perihelion, its speed has reached roughly 635,000 kilometers per hour. The mission was launched in 2018 to study the solar corona and the origin of the solar wind. Its speed record continues to stand as a major engineering and scientific achievement.